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Pull more MM updates from Andrew Morton:
- "zram: support algorithm-specific parameters" from Sergey Senozhatsky
adds infrastructure for passing algorithm-specific parameters into
zram. A single parameter `winbits' is implemented at this time.
- "memcg: nmi-safe kmem charging" from Shakeel Butt makes memcg
charging nmi-safe, which is required by BFP, which can operate in NMI
context.
- "Some random fixes and cleanup to shmem" from Kemeng Shi implements
small fixes and cleanups in the shmem code.
- "Skip mm selftests instead when kernel features are not present" from
Zi Yan fixes some issues in the MM selftest code.
- "mm/damon: build-enable essential DAMON components by default" from
SeongJae Park reworks DAMON Kconfig to make it easier to enable
CONFIG_DAMON.
- "sched/numa: add statistics of numa balance task migration" from Libo
Chen adds more info into sysfs and procfs files to improve visibility
into the NUMA balancer's task migration activity.
- "selftests/mm: cow and gup_longterm cleanups" from Mark Brown
provides various updates to some of the MM selftests to make them
play better with the overall containing framework.
* tag 'mm-stable-2025-06-01-14-06' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (43 commits)
mm/khugepaged: clean up refcount check using folio_expected_ref_count()
selftests/mm: fix test result reporting in gup_longterm
selftests/mm: report unique test names for each cow test
selftests/mm: add helper for logging test start and results
selftests/mm: use standard ksft_finished() in cow and gup_longterm
selftests/damon/_damon_sysfs: skip testcases if CONFIG_DAMON_SYSFS is disabled
sched/numa: add statistics of numa balance task
sched/numa: fix task swap by skipping kernel threads
tools/testing: check correct variable in open_procmap()
tools/testing/vma: add missing function stub
mm/gup: update comment explaining why gup_fast() disables IRQs
selftests/mm: two fixes for the pfnmap test
mm/khugepaged: fix race with folio split/free using temporary reference
mm: add CONFIG_PAGE_BLOCK_ORDER to select page block order
mmu_notifiers: remove leftover stub macros
selftests/mm: deduplicate test names in madv_populate
kcov: rust: add flags for KCOV with Rust
mm: rust: make CONFIG_MMU ifdefs more narrow
mmu_gather: move tlb flush for VM_PFNMAP/VM_MIXEDMAP vmas into free_pgtables()
mm/damon/Kconfig: enable CONFIG_DAMON by default
...
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All users of page->index have been converted to not refer to it any more.
Update a few pieces of documentation that were missed and prevent new
users from appearing (or at least make them easy to grep for).
Link: https://lkml.kernel.org/r/20250514181508.3019795-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Pull MM updates from Andrew Morton:
- "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
creating a pte which addresses the first page in a folio and reduces
the amount of plumbing which architecture must implement to provide
this.
- "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
largely unrelated folio infrastructure changes which clean things up
and better prepare us for future work.
- "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
Price adds early-init code to prevent x86 from leaving physical
memory unused when physical address regions are not aligned to memory
block size.
- "mm/compaction: allow more aggressive proactive compaction" from
Michal Clapinski provides some tuning of the (sadly, hard-coded (more
sadly, not auto-tuned)) thresholds for our invokation of proactive
compaction. In a simple test case, the reduction of a guest VM's
memory consumption was dramatic.
- "Minor cleanups and improvements to swap freeing code" from Kemeng
Shi provides some code cleaups and a small efficiency improvement to
this part of our swap handling code.
- "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
adds the ability for a ptracer to modify syscalls arguments. At this
time we can alter only "system call information that are used by
strace system call tampering, namely, syscall number, syscall
arguments, and syscall return value.
This series should have been incorporated into mm.git's "non-MM"
branch, but I goofed.
- "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
against /proc/pid/pagemap. This permits CRIU to more efficiently get
at the info about guard regions.
- "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
implements that fix. No runtime effect is expected because
validate_page_before_insert() happens to fix up this error.
- "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
Hildenbrand basically brings uprobe text poking into the current
decade. Remove a bunch of hand-rolled implementation in favor of
using more current facilities.
- "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
Khandual provides enhancements and generalizations to the pte dumping
code. This might be needed when 128-bit Page Table Descriptors are
enabled for ARM.
- "Always call constructor for kernel page tables" from Kevin Brodsky
ensures that the ctor/dtor is always called for kernel pgtables, as
it already is for user pgtables.
This permits the addition of more functionality such as "insert hooks
to protect page tables". This change does result in various
architectures performing unnecesary work, but this is fixed up where
it is anticipated to occur.
- "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
Ryhl adds plumbing to permit Rust access to core MM structures.
- "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
Stoakes takes advantage of some VMA merging opportunities which we've
been missing for 15 years.
- "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
SeongJae Park optimizes process_madvise()'s TLB flushing.
Instead of flushing each address range in the provided iovec, we
batch the flushing across all the iovec entries. The syscall's cost
was approximately halved with a microbenchmark which was designed to
load this particular operation.
- "Track node vacancy to reduce worst case allocation counts" from
Sidhartha Kumar makes the maple tree smarter about its node
preallocation.
stress-ng mmap performance increased by single-digit percentages and
the amount of unnecessarily preallocated memory was dramaticelly
reduced.
- "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
a few unnecessary things which Baoquan noted when reading the code.
- ""Enhance sysfs handling for memory hotplug in weighted interleave"
from Rakie Kim "enhances the weighted interleave policy in the memory
management subsystem by improving sysfs handling, fixing memory
leaks, and introducing dynamic sysfs updates for memory hotplug
support". Fixes things on error paths which we are unlikely to hit.
- "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
from SeongJae Park introduces new DAMOS quota goal metrics which
eliminate the manual tuning which is required when utilizing DAMON
for memory tiering.
- "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
provides cleanups and small efficiency improvements which Baoquan
found via code inspection.
- "vmscan: enforce mems_effective during demotion" from Gregory Price
changes reclaim to respect cpuset.mems_effective during demotion when
possible. because presently, reclaim explicitly ignores
cpuset.mems_effective when demoting, which may cause the cpuset
settings to violated.
This is useful for isolating workloads on a multi-tenant system from
certain classes of memory more consistently.
- "Clean up split_huge_pmd_locked() and remove unnecessary folio
pointers" from Gavin Guo provides minor cleanups and efficiency gains
in in the huge page splitting and migrating code.
- "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
for `struct mem_cgroup', yielding improved memory utilization.
- "add max arg to swappiness in memory.reclaim and lru_gen" from
Zhongkun He adds a new "max" argument to the "swappiness=" argument
for memory.reclaim MGLRU's lru_gen.
This directs proactive reclaim to reclaim from only anon folios
rather than file-backed folios.
- "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
first step on the path to permitting the kernel to maintain existing
VMs while replacing the host kernel via file-based kexec. At this
time only memblock's reserve_mem is preserved.
- "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
and uses a smarter way of looping over a pfn range. By skipping
ranges of invalid pfns.
- "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
when a task is pinned a single NUMA mode.
Dramatic performance benefits were seen in some real world cases.
- "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
Garg addresses a warning which occurs during memory compaction when
using JFS.
- "move all VMA allocation, freeing and duplication logic to mm" from
Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
appropriate mm/vma.c.
- "mm, swap: clean up swap cache mapping helper" from Kairui Song
provides code consolidation and cleanups related to the folio_index()
function.
- "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.
- "memcg: Fix test_memcg_min/low test failures" from Waiman Long
addresses some bogus failures which are being reported by the
test_memcontrol selftest.
- "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
Stoakes commences the deprecation of file_operations.mmap() in favor
of the new file_operations.mmap_prepare().
The latter is more restrictive and prevents drivers from messing with
things in ways which, amongst other problems, may defeat VMA merging.
- "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
the per-cpu memcg charge cache from the objcg's one.
This is a step along the way to making memcg and objcg charging
NMI-safe, which is a BPF requirement.
- "mm/damon: minor fixups and improvements for code, tests, and
documents" from SeongJae Park is yet another batch of miscellaneous
DAMON changes. Fix and improve minor problems in code, tests and
documents.
- "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
stats to be irq safe. Another step along the way to making memcg
charging and stats updates NMI-safe, a BPF requirement.
- "Let unmap_hugepage_range() and several related functions take folio
instead of page" from Fan Ni provides folio conversions in the
hugetlb code.
* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
mm: pcp: increase pcp->free_count threshold to trigger free_high
mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
mm/hugetlb: pass folio instead of page to unmap_ref_private()
memcg: objcg stock trylock without irq disabling
memcg: no stock lock for cpu hot-unplug
memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
memcg: make count_memcg_events re-entrant safe against irqs
memcg: make mod_memcg_state re-entrant safe against irqs
memcg: move preempt disable to callers of memcg_rstat_updated
memcg: memcg_rstat_updated re-entrant safe against irqs
mm: khugepaged: decouple SHMEM and file folios' collapse
selftests/eventfd: correct test name and improve messages
alloc_tag: check mem_profiling_support in alloc_tag_init
Docs/damon: update titles and brief introductions to explain DAMOS
selftests/damon/_damon_sysfs: read tried regions directories in order
mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
...
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Pull networking updates from Paolo Abeni:
"Core:
- Implement the Device Memory TCP transmit path, allowing zero-copy
data transmission on top of TCP from e.g. GPU memory to the wire.
- Move all the IPv6 routing tables management outside the RTNL scope,
under its own lock and RCU. The route control path is now 3x times
faster.
- Convert queue related netlink ops to instance lock, reducing again
the scope of the RTNL lock. This improves the control plane
scalability.
- Refactor the software crc32c implementation, removing unneeded
abstraction layers and improving significantly the related
micro-benchmarks.
- Optimize the GRO engine for UDP-tunneled traffic, for a 10%
performance improvement in related stream tests.
- Cover more per-CPU storage with local nested BH locking; this is a
prep work to remove the current per-CPU lock in local_bh_disable()
on PREMPT_RT.
- Introduce and use nlmsg_payload helper, combining buffer bounds
verification with accessing payload carried by netlink messages.
Netfilter:
- Rewrite the procfs conntrack table implementation, improving
considerably the dump performance. A lot of user-space tools still
use this interface.
- Implement support for wildcard netdevice in netdev basechain and
flowtables.
- Integrate conntrack information into nft trace infrastructure.
- Export set count and backend name to userspace, for better
introspection.
BPF:
- BPF qdisc support: BPF-qdisc can be implemented with BPF struct_ops
programs and can be controlled in similar way to traditional qdiscs
using the "tc qdisc" command.
- Refactor the UDP socket iterator, addressing long standing issues
WRT duplicate hits or missed sockets.
Protocols:
- Improve TCP receive buffer auto-tuning and increase the default
upper bound for the receive buffer; overall this improves the
single flow maximum thoughput on 200Gbs link by over 60%.
- Add AFS GSSAPI security class to AF_RXRPC; it provides transport
security for connections to the AFS fileserver and VL server.
- Improve TCP multipath routing, so that the sources address always
matches the nexthop device.
- Introduce SO_PASSRIGHTS for AF_UNIX, to allow disabling SCM_RIGHTS,
and thus preventing DoS caused by passing around problematic FDs.
- Retire DCCP socket. DCCP only receives updates for bugs, and major
distros disable it by default. Its removal allows for better
organisation of TCP fields to reduce the number of cache lines hit
in the fast path.
- Extend TCP drop-reason support to cover PAWS checks.
Driver API:
- Reorganize PTP ioctl flag support to require an explicit opt-in for
the drivers, avoiding the problem of drivers not rejecting new
unsupported flags.
- Converted several device drivers to timestamping APIs.
- Introduce per-PHY ethtool dump helpers, improving the support for
dump operations targeting PHYs.
Tests and tooling:
- Add support for classic netlink in user space C codegen, so that
ynl-c can now read, create and modify links, routes addresses and
qdisc layer configuration.
- Add ynl sub-types for binary attributes, allowing ynl-c to output
known struct instead of raw binary data, clarifying the classic
netlink output.
- Extend MPTCP selftests to improve the code-coverage.
- Add tests for XDP tail adjustment in AF_XDP.
New hardware / drivers:
- OpenVPN virtual driver: offload OpenVPN data channels processing to
the kernel-space, increasing the data transfer throughput WRT the
user-space implementation.
- Renesas glue driver for the gigabit ethernet RZ/V2H(P) SoC.
- Broadcom asp-v3.0 ethernet driver.
- AMD Renoir ethernet device.
- ReakTek MT9888 2.5G ethernet PHY driver.
- Aeonsemi 10G C45 PHYs driver.
Drivers:
- Ethernet high-speed NICs:
- nVidia/Mellanox (mlx5):
- refactor the steering table handling to significantly
reduce the amount of memory used
- add support for complex matches in H/W flow steering
- improve flow streeing error handling
- convert to netdev instance locking
- Intel (100G, ice, igb, ixgbe, idpf):
- ice: add switchdev support for LLDP traffic over VF
- ixgbe: add firmware manipulation and regions devlink support
- igb: introduce support for frame transmission premption
- igb: adds persistent NAPI configuration
- idpf: introduce RDMA support
- idpf: add initial PTP support
- Meta (fbnic):
- extend hardware stats coverage
- add devlink dev flash support
- Broadcom (bnxt):
- add support for RX-side device memory TCP
- Wangxun (txgbe):
- implement support for udp tunnel offload
- complete PTP and SRIOV support for AML 25G/10G devices
- Ethernet NICs embedded and virtual:
- Google (gve):
- add device memory TCP TX support
- Amazon (ena):
- support persistent per-NAPI config
- Airoha:
- add H/W support for L2 traffic offload
- add per flow stats for flow offloading
- RealTek (rtl8211): add support for WoL magic packet
- Synopsys (stmmac):
- dwmac-socfpga 1000BaseX support
- add Loongson-2K3000 support
- introduce support for hardware-accelerated VLAN stripping
- Broadcom (bcmgenet):
- expose more H/W stats
- Freescale (enetc, dpaa2-eth):
- enetc: add MAC filter, VLAN filter RSS and loopback support
- dpaa2-eth: convert to H/W timestamping APIs
- vxlan: convert FDB table to rhashtable, for better scalabilty
- veth: apply qdisc backpressure on full ring to reduce TX drops
- Ethernet switches:
- Microchip (kzZ88x3): add ETS scheduler support
- Ethernet PHYs:
- RealTek (rtl8211):
- add support for WoL magic packet
- add support for PHY LEDs
- CAN:
- Adds RZ/G3E CANFD support to the rcar_canfd driver.
- Preparatory work for CAN-XL support.
- Add self-tests framework with support for CAN physical interfaces.
- WiFi:
- mac80211:
- scan improvements with multi-link operation (MLO)
- Qualcomm (ath12k):
- enable AHB support for IPQ5332
- add monitor interface support to QCN9274
- add multi-link operation support to WCN7850
- add 802.11d scan offload support to WCN7850
- monitor mode for WCN7850, better 6 GHz regulatory
- Qualcomm (ath11k):
- restore hibernation support
- MediaTek (mt76):
- WiFi-7 improvements
- implement support for mt7990
- Intel (iwlwifi):
- enhanced multi-link single-radio (EMLSR) support on 5 GHz links
- rework device configuration
- RealTek (rtw88):
- improve throughput for RTL8814AU
- RealTek (rtw89):
- add multi-link operation support
- STA/P2P concurrency improvements
- support different SAR configs by antenna
- Bluetooth:
- introduce HCI Driver protocol
- btintel_pcie: do not generate coredump for diagnostic events
- btusb: add HCI Drv commands for configuring altsetting
- btusb: add RTL8851BE device 0x0bda:0xb850
- btusb: add new VID/PID 13d3/3584 for MT7922
- btusb: add new VID/PID 13d3/3630 and 13d3/3613 for MT7925
- btnxpuart: implement host-wakeup feature"
* tag 'net-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1611 commits)
selftests/bpf: Fix bpf selftest build warning
selftests: netfilter: Fix skip of wildcard interface test
net: phy: mscc: Stop clearing the the UDPv4 checksum for L2 frames
net: openvswitch: Fix the dead loop of MPLS parse
calipso: Don't call calipso functions for AF_INET sk.
selftests/tc-testing: Add a test for HFSC eltree double add with reentrant enqueue behaviour on netem
net_sched: hfsc: Address reentrant enqueue adding class to eltree twice
octeontx2-pf: QOS: Refactor TC_HTB_LEAF_DEL_LAST callback
octeontx2-pf: QOS: Perform cache sync on send queue teardown
net: mana: Add support for Multi Vports on Bare metal
net: devmem: ncdevmem: remove unused variable
net: devmem: ksft: upgrade rx test to send 1K data
net: devmem: ksft: add 5 tuple FS support
net: devmem: ksft: add exit_wait to make rx test pass
net: devmem: ksft: add ipv4 support
net: devmem: preserve sockc_err
page_pool: fix ugly page_pool formatting
net: devmem: move list_add to net_devmem_bind_dmabuf.
selftests: netfilter: nft_queue.sh: include file transfer duration in log message
net: phy: mscc: Fix memory leak when using one step timestamping
...
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In do_set_pmd(), we always use the folio->page to build PMD mappings for
the entire folio. Since all callers of do_set_pmd() already hold a stable
folio, converting do_set_pmd() to take a folio is safe and more
straightforward.
In addition, to ensure the extensibility of do_set_pmd() for supporting
larger folios beyond PMD size, we keep the 'page' parameter to specify
which page within the folio should be mapped.
No functional changes expected.
Link: https://lkml.kernel.org/r/9b488f4ecb4d3fd8634e3d448dd0ed6964482480.1747017104.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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It's unused, so let's remove it.
Link: https://lkml.kernel.org/r/20250512123424.637989-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org> [x86 bits]
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Airlie <airlied@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Tvrtko Ursulin <tursulin@ursulin.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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On configs with CONFIG_ARM64_GCS=y, VM_SHADOW_STACK is bit 38. On configs
with CONFIG_HAVE_ARCH_USERFAULTFD_MINOR=y (selected by CONFIG_ARM64 when
CONFIG_USERFAULTFD=y), VM_UFFD_MINOR is _also_ bit 38.
This bit being shared by two different VMA flags could lead to all sorts
of unintended behaviors. Presumably, a process could maybe call into
userfaultfd in a way that disables the shadow stack vma flag. I can't
think of any attack where this would help (presumably, if an attacker
tries to disable shadow stacks, they are trying to hijack control flow so
can't arbitrarily call into userfaultfd yet anyway) but this still feels
somewhat scary.
Link: https://lkml.kernel.org/r/20250507131000.1204175-2-revest@chromium.org
Fixes: ae80e1629aea ("mm: Define VM_SHADOW_STACK for arm64 when we support GCS")
Signed-off-by: Florent Revest <revest@chromium.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Florent Revest <revest@chromium.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "move all VMA allocation, freeing and duplication logic to
mm", v3.
Currently VMA allocation, freeing and duplication exist in kernel/fork.c,
which is a violation of separation of concerns, and leaves these functions
exposed to the rest of the kernel when they are in fact internal
implementation details.
Resolve this by moving this logic to mm, and making it internal to vma.c,
vma.h.
This also allows us, in future, to provide userland testing around this
functionality.
We additionally abstract dup_mmap() to mm, being careful to ensure
kernel/fork.c acceses this via the mm internal header so it is not exposed
elsewhere in the kernel.
As part of this change, also abstract initial stack allocation performed
in __bprm_mm_init() out of fs code into mm via the
create_init_stack_vma(), as this code uses vm_area_alloc() and
vm_area_free().
In order to do so sensibly, we introduce a new mm/vma_exec.c file, which
contains the code that is shared by mm and exec. This file is added to
both memory mapping and exec sections in MAINTAINERS so both sets of
maintainers can maintain oversight.
As part of this change, we also move relocate_vma_down() to mm/vma_exec.c
so all shared mm/exec functionality is kept in one place.
We add code shared between nommu and mmu-enabled configurations in order
to share VMA allocation, freeing and duplication code correctly while also
keeping these functions available in userland VMA testing.
This is achieved by adding a mm/vma_init.c file which is also compiled by
the userland tests.
This patch (of 4):
There is functionality that overlaps the exec and memory mapping
subsystems. While it properly belongs in mm, it is important that exec
maintainers maintain oversight of this functionality correctly.
We can establish both goals by adding a new mm/vma_exec.c file which
contains these 'glue' functions, and have fs/exec.c import them.
As a part of this change, to ensure that proper oversight is achieved, add
the file to both the MEMORY MAPPING and EXEC & BINFMT API, ELF sections.
scripts/get_maintainer.pl can correctly handle files in multiple entries
and this neatly handles the cross-over.
[akpm@linux-foundation.org: fix comment typo]
Link: https://lkml.kernel.org/r/80f0d0c6-0b68-47f9-ab78-0ab7f74677fc@lucifer.local
Link: https://lkml.kernel.org/r/cover.1745853549.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/91f2cee8f17d65214a9d83abb7011aa15f1ea690.1745853549.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series " JFS: Implement migrate_folio for jfs_metapage_aops" v5.
This patchset addresses a warning that occurs during memory compaction due
to JFS's missing migrate_folio operation. The warning was introduced by
commit 7ee3647243e5 ("migrate: Remove call to ->writepage") which added
explicit warnings when filesystem don't implement migrate_folio.
The syzbot reported following [1]:
jfs_metapage_aops does not implement migrate_folio
WARNING: CPU: 1 PID: 5861 at mm/migrate.c:955 fallback_migrate_folio mm/migrate.c:953 [inline]
WARNING: CPU: 1 PID: 5861 at mm/migrate.c:955 move_to_new_folio+0x70e/0x840 mm/migrate.c:1007
Modules linked in:
CPU: 1 UID: 0 PID: 5861 Comm: syz-executor280 Not tainted 6.15.0-rc1-next-20250411-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:fallback_migrate_folio mm/migrate.c:953 [inline]
RIP: 0010:move_to_new_folio+0x70e/0x840 mm/migrate.c:1007
To fix this issue, this series implement metapage_migrate_folio() for JFS
which handles both single and multiple metapages per page configurations.
While most filesystems leverage existing migration implementations like
filemap_migrate_folio(), buffer_migrate_folio_norefs() or
buffer_migrate_folio() (which internally used folio_expected_refs()),
JFS's metapage architecture requires special handling of its private data
during migration. To support this, this series introduce the
folio_expected_ref_count(), which calculates external references to a
folio from page/swap cache, private data, and page table mappings.
This standardized implementation replaces the previous ad-hoc
folio_expected_refs() function and enables JFS to accurately determine
whether a folio has unexpected references before attempting migration.
Implement folio_expected_ref_count() to calculate expected folio reference
counts from:
- Page/swap cache (1 per page)
- Private data (1)
- Page table mappings (1 per map)
While originally needed for page migration operations, this improved
implementation standardizes reference counting by consolidating all
refcount contributors into a single, reusable function that can benefit
any subsystem needing to detect unexpected references to folios.
The folio_expected_ref_count() returns the sum of these external
references without including any reference the caller itself might hold.
Callers comparing against the actual folio_ref_count() must account for
their own references separately.
Link: https://syzkaller.appspot.com/bug?extid=8bb6fd945af4e0ad9299 [1]
Link: https://lkml.kernel.org/r/20250430100150.279751-1-shivankg@amd.com
Link: https://lkml.kernel.org/r/20250430100150.279751-2-shivankg@amd.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Co-developed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
To prevent the function from being used when CONFIG_MM_ID is disabled, we
intend to inline it into its few callers, which also would help maintain
the expected code placement.
Link: https://lkml.kernel.org/r/20250424155606.57488-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Mingzhe Yang <mingzhe.yang@ly.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Currently the VMA and mmap locking logic is entangled in two of the most
overwrought files in mm - include/linux/mm.h and mm/memory.c. Separate
this logic out so we can more easily make changes and create an
appropriate MAINTAINERS entry that spans only the logic relating to
locking.
This should have no functional change. Care is taken to avoid dependency
loops, we must regrettably keep release_fault_lock() and
assert_fault_locked() in mm.h as a result due to the dependence on the
vm_fault type.
Additionally we must declare rcuwait_wake_up() manually to avoid a
dependency cycle on linux/rcuwait.h.
Additionally move the nommu implementatino of lock_mm_and_find_vma() to
mmap_lock.c so everything lock-related is in one place.
Link: https://lkml.kernel.org/r/bec6c8e29fa8de9267a811a10b1bdae355d67ed4.1744799282.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Split page table locks are not used for pgtables associated to init_mm, at
any level. pte_alloc_kernel() does not call ptlock_init() as a result.
There is however no separate alloc/free functions for kernel PMDs, and
pmd_ptlock_init() is called unconditionally. When ALLOC_SPLIT_PTLOCKS is
true (e.g. 32-bit architectures or if CONFIG_PREEMPT_RT is selected),
this results in unnecessary dynamic memory allocation every time a kernel
PMD is allocated.
Now that pagetable_pmd_ctor() is passed the associated mm, we can easily
remove this overhead by skipping pmd_ptlock_init() if the pgtable is
associated to init_mm. No special-casing is needed on the dtor path, as
ptlock_free() is already called unconditionally for all levels.
(ptlock_free() is a no-op unless a ptlock was allocated for the given
PTP.)
Link: https://lkml.kernel.org/r/20250408095222.860601-8-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Waleij <linus.walleij@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <x86@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Since [1], constructors/destructors are expected to be called for all page
table pages, at all levels and for both user and kernel pgtables. There
is however one glaring exception: kernel PTEs are managed via separate
helpers (pte_alloc_kernel/pte_free_kernel), which do not call the [cd]tor,
at least not in the generic implementation.
The most obvious reason for this anomaly is that init_mm is special-cased
not to use split page table locks. As a result calling ptlock_init() for
PTEs associated with init_mm would be wasteful, potentially resulting in
dynamic memory allocation. However, pgtable [cd]tors perform other
actions - currently related to accounting/statistics, and potentially more
functionally significant in the future.
Now that pagetable_pte_ctor() is passed the associated mm, we can make it
skip the call to ptlock_init() for init_mm; this allows us to call the
ctor from pte_alloc_one_kernel() too. This is matched by a call to the
pgtable destructor in pte_free_kernel(); no special-casing is needed on
that path, as ptlock_free() is already called unconditionally.
(ptlock_free() is a no-op unless a ptlock was allocated for the given
PTP.)
This patch ensures that all architectures that rely on
<asm-generic/pgalloc.h> call the [cd]tor for kernel PTEs.
pte_free_kernel() cannot be overridden so changing the generic
implementation is sufficient. pte_alloc_one_kernel() can be overridden
using __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL, and a few architectures implement
it by calling the page allocator directly. We amend those so that they
call the generic __pte_alloc_one_kernel() instead, if possible, ensuring
that the ctor is called.
A few architectures do not use <asm-generic/pgalloc.h>; those will be
taken care of separately.
[1] https://lore.kernel.org/linux-mm/20250103184415.2744423-1-kevin.brodsky@arm.com/
Link: https://lkml.kernel.org/r/20250408095222.860601-4-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> # s390
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Waleij <linus.walleij@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <x86@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Always call constructor for kernel page tables", v2.
There has been much confusion around exactly when page table
constructors/destructors (pagetable_*_[cd]tor) are supposed to be called.
They were initially introduced for user PTEs only (to support split page
table locks), then at the PMD level for the same purpose. Accounting was
added later on, starting at the PTE level and then moving to higher levels
(PMD, PUD). Finally, with my earlier series "Account page tables at all
levels" [1], the ctor/dtor is run for all levels, all the way to PGD.
I thought this was the end of the story, and it hopefully is for user
pgtables, but I was wrong for what concerns kernel pgtables. The current
situation there makes very little sense:
* At the PTE level, the ctor/dtor is not called (at least in the generic
implementation). Specific helpers are used for kernel pgtables at this
level (pte_{alloc,free}_kernel()) and those have never called the
ctor/dtor, most likely because they were initially irrelevant in the
kernel case.
* At all other levels, the ctor/dtor is normally called. This is
potentially wasteful at the PMD level (more on that later).
This series aims to ensure that the ctor/dtor is always called for kernel
pgtables, as it already is for user pgtables. Besides consistency, the
main motivation is to guarantee that ctor/dtor hooks are systematically
called; this makes it possible to insert hooks to protect page tables [2],
for instance. There is however an extra challenge: split locks are not
used for kernel pgtables, and it would therefore be wasteful to initialise
them (ptlock_init()).
It is worth clarifying exactly when split locks are used. They clearly
are for user pgtables, but as illustrated in commit 61444cde9170 ("ARM:
8591/1: mm: use fully constructed struct pages for EFI pgd allocations"),
they also are for special page tables like efi_mm. The one case where
split locks are definitely unused is pgtables owned by init_mm; this is
consistent with the behaviour of apply_to_pte_range().
The approach chosen in this series is therefore to pass the mm associated
to the pgtables being constructed to pagetable_{pte,pmd}_ctor() (patch 1),
and skip ptlock_init() if mm == &init_mm (patch 3 and 7). This makes it
possible to call the PTE ctor/dtor from pte_{alloc,free}_kernel() without
unintended consequences (patch 3). As a result the accounting functions
are now called at all levels for kernel pgtables, and split locks are
never initialised.
In configurations where ptlocks are dynamically allocated (32-bit,
PREEMPT_RT, etc.) and ARCH_ENABLE_SPLIT_PMD_PTLOCK is selected, this
series results in the removal of a kmem_cache allocation for every kernel
PMD. Additionally, for certain architectures that do not use
<asm-generic/pgalloc.h> such as s390, the same optimisation occurs at the
PTE level.
===
Things get more complicated when it comes to special pgtable allocators
(patch 8-12). All architectures need such allocators to create initial
kernel pgtables; we are not concerned with those as the ctor cannot be
called so early in the boot sequence. However, those allocators may also
be used later in the boot sequence or during normal operations. There are
two main use-cases:
1. Mapping EFI memory: efi_mm (arm, arm64, riscv)
2. arch_add_memory(): init_mm
The ctor is already explicitly run (at the PTE/PMD level) in the first
case, as required for pgtables that are not associated with init_mm.
However the same allocators may also be used for the second use-case (or
others), and this is where it gets messy. Patch 1 calls the ctor with
NULL as mm in those situations, as the actual mm isn't available.
Practically this means that ptlocks will be unconditionally initialised.
This is fine on arm - create_mapping_late() is only used for the EFI
mapping. On arm64, __create_pgd_mapping() is also used by
arch_add_memory(); patch 8/9/11 ensure that ctors are called at all levels
with the appropriate mm. The situation is similar on riscv, but
propagating the mm down to the ctor would require significant refactoring.
Since they are already called unconditionally, this series leaves riscv
no worse off - patch 10 adds comments to clarify the situation.
From a cursory look at other architectures implementing arch_add_memory(),
s390 and x86 may also need a similar treatment to add constructor calls.
This is to be taken care of in a future version or as a follow-up.
===
The complications in those special pgtable allocators beg the question:
does it really make sense to treat efi_mm and init_mm differently in e.g.
apply_to_pte_range()? Maybe what we really need is a way to tell if an mm
corresponds to user memory or not, and never use split locks for non-user
mm's. Feedback and suggestions welcome!
This patch (of 12):
In preparation for calling constructors for all kernel page tables while
eliding unnecessary ptlock initialisation, let's pass down the associated
mm to the PTE/PMD level ctors. (These are the two levels where ptlocks
are used.)
In most cases the mm is already around at the point of calling the ctor so
we simply pass it down. This is however not the case for special page
table allocators:
* arch/arm/mm/mmu.c
* arch/arm64/mm/mmu.c
* arch/riscv/mm/init.c
In those cases, the page tables being allocated are either for standard
kernel memory (init_mm) or special page directories, which may not be
associated to any mm. For now let's pass NULL as mm; this will be refined
where possible in future patches.
No functional change in this patch.
Link: https://lore.kernel.org/linux-mm/20250103184415.2744423-1-kevin.brodsky@arm.com/ [1]
Link: https://lore.kernel.org/linux-hardening/20250203101839.1223008-1-kevin.brodsky@arm.com/ [2]
Link: https://lkml.kernel.org/r/20250408095222.860601-1-kevin.brodsky@arm.com
Link: https://lkml.kernel.org/r/20250408095222.860601-2-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> [s390]
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Linus Waleij <linus.walleij@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: <x86@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
mm_struct.hiwater_rss can be accessed concurrently without proper
synchronization as reported by KCSAN.
This data race is benign as it only affects accounting information.
Annotate it with data_race() to make KCSAN happy.
Link: https://lkml.kernel.org/r/20250331-mm-maxrss-data-race-v2-1-cf958e6205bf@iencinas.com
Signed-off-by: Ignacio Encinas <ignacio@iencinas.com>
Reported-by: syzbot+419c4b42acc36c420ad3@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67e3390c.050a0220.1ec46.0001.GAE@google.com/
Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All callers now use folio_nr_pages(). Delete this wrapper.
Link: https://lkml.kernel.org/r/20250402210612.2444135-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All callers have been converted to call offset_in_folio().
Link: https://lkml.kernel.org/r/20250402210612.2444135-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Removes five conversions from folio to page. Also removes both callers of
mk_pmd() that aren't part of mk_huge_pmd(), getting us a step closer to
removing the confusion between mk_pmd(), mk_huge_pmd() and pmd_mkhuge().
Link: https://lkml.kernel.org/r/20250402181709.2386022-11-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Richard Weinberger <richard@nod.at>
Cc: <x86@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove a cast from folio to page in four callers of mk_pte().
Link: https://lkml.kernel.org/r/20250402181709.2386022-8-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Richard Weinberger <richard@nod.at>
Cc: <x86@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All architectures now use the common mk_pte() definition, so we can remove
the condition.
Link: https://lkml.kernel.org/r/20250402181709.2386022-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Richard Weinberger <richard@nod.at>
Cc: <x86@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Most architectures simply call pfn_pte(). Centralise that as the normal
definition and remove the definition of mk_pte() from the architectures
which have either that exact definition or something similar.
Link: https://lkml.kernel.org/r/20250402181709.2386022-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> # s390
Cc: Zi Yan <ziy@nvidia.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Richard Weinberger <richard@nod.at>
Cc: <x86@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Cross-merge networking fixes after downstream PR (net-6.15-rc4).
This pull includes wireless and a fix to vxlan which isn't
in Linus's tree just yet. The latter creates with a silent conflict
/ build breakage, so merging it now to avoid causing problems.
drivers/net/vxlan/vxlan_vnifilter.c
094adad91310 ("vxlan: Use a single lock to protect the FDB table")
087a9eb9e597 ("vxlan: vnifilter: Fix unlocked deletion of default FDB entry")
https://lore.kernel.org/20250423145131.513029-1-idosch@nvidia.com
No "normal" conflicts, or adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Alison reports an issue with fsdax when large extends end up using large
ZONE_DEVICE folios:
[ 417.796271] BUG: kernel NULL pointer dereference, address: 0000000000000b00
[ 417.796982] #PF: supervisor read access in kernel mode
[ 417.797540] #PF: error_code(0x0000) - not-present page
[ 417.798123] PGD 2a5c5067 P4D 2a5c5067 PUD 2a5c6067 PMD 0
[ 417.798690] Oops: Oops: 0000 [#1] SMP NOPTI
[ 417.799178] CPU: 5 UID: 0 PID: 1515 Comm: mmap Tainted: ...
[ 417.800150] Tainted: [O]=OOT_MODULE
[ 417.800583] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[ 417.801358] RIP: 0010:__lruvec_stat_mod_folio+0x7e/0x250
[ 417.801948] Code: ...
[ 417.803662] RSP: 0000:ffffc90002be3a08 EFLAGS: 00010206
[ 417.804234] RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000000002
[ 417.804984] RDX: ffffffff815652d7 RSI: 0000000000000000 RDI: ffffffff82a2beae
[ 417.805689] RBP: ffffc90002be3a28 R08: 0000000000000000 R09: 0000000000000000
[ 417.806384] R10: ffffea0007000040 R11: ffff888376ffe000 R12: 0000000000000001
[ 417.807099] R13: 0000000000000012 R14: ffff88807fe4ab40 R15: ffff888029210580
[ 417.807801] FS: 00007f339fa7a740(0000) GS:ffff8881fa9b9000(0000) knlGS:0000000000000000
[ 417.808570] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 417.809193] CR2: 0000000000000b00 CR3: 000000002a4f0004 CR4: 0000000000370ef0
[ 417.809925] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 417.810622] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 417.811353] Call Trace:
[ 417.811709] <TASK>
[ 417.812038] folio_add_file_rmap_ptes+0x143/0x230
[ 417.812566] insert_page_into_pte_locked+0x1ee/0x3c0
[ 417.813132] insert_page+0x78/0xf0
[ 417.813558] vmf_insert_page_mkwrite+0x55/0xa0
[ 417.814088] dax_fault_iter+0x484/0x7b0
[ 417.814542] dax_iomap_pte_fault+0x1ca/0x620
[ 417.815055] dax_iomap_fault+0x39/0x40
[ 417.815499] __xfs_write_fault+0x139/0x380
[ 417.815995] ? __handle_mm_fault+0x5e5/0x1a60
[ 417.816483] xfs_write_fault+0x41/0x50
[ 417.816966] xfs_filemap_fault+0x3b/0xe0
[ 417.817424] __do_fault+0x31/0x180
[ 417.817859] __handle_mm_fault+0xee1/0x1a60
[ 417.818325] ? debug_smp_processor_id+0x17/0x20
[ 417.818844] handle_mm_fault+0xe1/0x2b0
[...]
The issue is that when we split a large ZONE_DEVICE folio to order-0 ones,
we don't reset the order/_nr_pages. As folio->_nr_pages overlays
page[1]->memcg_data, once page[1] is a folio, it suddenly looks like it
has folio->memcg_data set. And we never manually initialize
folio->memcg_data in fsdax code, because we never expect it to be set at
all.
When __lruvec_stat_mod_folio() then stumbles over such a folio, it tries
to use folio->memcg_data (because it's non-NULL) but it does not actually
point at a memcg, resulting in the problem.
Alison also observed that these folios sometimes have "locked" set, which
is rather concerning (folios locked from the beginning ...). The reason
is that the order for large folios is stored in page[1]->flags, which
become the folio->flags of a new small folio.
Let's fix it by adding a folio helper to clear order/_nr_pages for
splitting purposes.
Maybe we should reinitialize other large folio flags / folio members as
well when splitting, because they might similarly cause harm once page[1]
becomes a folio? At least other flags in PAGE_FLAGS_SECOND should not be
set for fsdax, so at least page[1]->flags might be as expected with this
fix.
From a quick glimpse, initializing ->mapping, ->pgmap and ->share should
re-initialize most things from a previous page[1] used by large folios
that fsdax cares about. For example folio->private might not get
reinitialized, but maybe that's not relevant -- no traces of it's use in
fsdax code. Needs a closer look.
Another thing that should be considered in the future is performing
similar checks as we perform in free_tail_page_prepare()
-- checking pincount etc.
-- when freeing a large fsdax folio.
Link: https://lkml.kernel.org/r/20250410091020.119116-1-david@redhat.com
Fixes: 4996fc547f5b ("mm: let _folio_nr_pages overlay memcg_data in first tail page")
Fixes: 38607c62b34b ("fs/dax: properly refcount fs dax pages")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Alison Schofield <alison.schofield@intel.com>
Closes: https://lkml.kernel.org/r/Z_W9Oeg-D9FhImf3@aschofie-mobl2.lan
Tested-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: "Darrick J. Wong" <djwong@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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When enabling DMA mapping in page_pool, pages are kept DMA mapped until
they are released from the pool, to avoid the overhead of re-mapping the
pages every time they are used. This causes resource leaks and/or
crashes when there are pages still outstanding while the device is torn
down, because page_pool will attempt an unmap through a non-existent DMA
device on the subsequent page return.
To fix this, implement a simple tracking of outstanding DMA-mapped pages
in page pool using an xarray. This was first suggested by Mina[0], and
turns out to be fairly straight forward: We simply store pointers to
pages directly in the xarray with xa_alloc() when they are first DMA
mapped, and remove them from the array on unmap. Then, when a page pool
is torn down, it can simply walk the xarray and unmap all pages still
present there before returning, which also allows us to get rid of the
get/put_device() calls in page_pool. Using xa_cmpxchg(), no additional
synchronisation is needed, as a page will only ever be unmapped once.
To avoid having to walk the entire xarray on unmap to find the page
reference, we stash the ID assigned by xa_alloc() into the page
structure itself, using the upper bits of the pp_magic field. This
requires a couple of defines to avoid conflicting with the
POINTER_POISON_DELTA define, but this is all evaluated at compile-time,
so does not affect run-time performance. The bitmap calculations in this
patch gives the following number of bits for different architectures:
- 23 bits on 32-bit architectures
- 21 bits on PPC64 (because of the definition of ILLEGAL_POINTER_VALUE)
- 32 bits on other 64-bit architectures
Stashing a value into the unused bits of pp_magic does have the effect
that it can make the value stored there lie outside the unmappable
range (as governed by the mmap_min_addr sysctl), for architectures that
don't define ILLEGAL_POINTER_VALUE. This means that if one of the
pointers that is aliased to the pp_magic field (such as page->lru.next)
is dereferenced while the page is owned by page_pool, that could lead to
a dereference into userspace, which is a security concern. The risk of
this is mitigated by the fact that (a) we always clear pp_magic before
releasing a page from page_pool, and (b) this would need a
use-after-free bug for struct page, which can have many other risks
since page->lru.next is used as a generic list pointer in multiple
places in the kernel. As such, with this patch we take the position that
this risk is negligible in practice. For more discussion, see[1].
Since all the tracking added in this patch is performed on DMA
map/unmap, no additional code is needed in the fast path, meaning the
performance overhead of this tracking is negligible there. A
micro-benchmark shows that the total overhead of the tracking itself is
about 400 ns (39 cycles(tsc) 395.218 ns; sum for both map and unmap[2]).
Since this cost is only paid on DMA map and unmap, it seems like an
acceptable cost to fix the late unmap issue. Further optimisation can
narrow the cases where this cost is paid (for instance by eliding the
tracking when DMA map/unmap is a no-op).
The extra memory needed to track the pages is neatly encapsulated inside
xarray, which uses the 'struct xa_node' structure to track items. This
structure is 576 bytes long, with slots for 64 items, meaning that a
full node occurs only 9 bytes of overhead per slot it tracks (in
practice, it probably won't be this efficient, but in any case it should
be an acceptable overhead).
[0] https://lore.kernel.org/all/CAHS8izPg7B5DwKfSuzz-iOop_YRbk3Sd6Y4rX7KBG9DcVJcyWg@mail.gmail.com/
[1] https://lore.kernel.org/r/20250320023202.GA25514@openwall.com
[2] https://lore.kernel.org/r/ae07144c-9295-4c9d-a400-153bb689fe9e@huawei.com
Reported-by: Yonglong Liu <liuyonglong@huawei.com>
Closes: https://lore.kernel.org/r/8743264a-9700-4227-a556-5f931c720211@huawei.com
Fixes: ff7d6b27f894 ("page_pool: refurbish version of page_pool code")
Suggested-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Jesper Dangaard Brouer <hawk@kernel.org>
Tested-by: Jesper Dangaard Brouer <hawk@kernel.org>
Tested-by: Qiuling Ren <qren@redhat.com>
Tested-by: Yuying Ma <yuma@redhat.com>
Tested-by: Yonglong Liu <liuyonglong@huawei.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409-page-pool-track-dma-v9-2-6a9ef2e0cba8@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
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Since we are about to stash some more information into the pp_magic
field, let's move the magic signature checks into a pair of helper
functions so it can be changed in one place.
Reviewed-by: Mina Almasry <almasrymina@google.com>
Tested-by: Yonglong Liu <liuyonglong@huawei.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409-page-pool-track-dma-v9-1-6a9ef2e0cba8@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Pull more MM updates from Andrew Morton:
- The series "mm: fixes for fallouts from mem_init() cleanup" from Mike
Rapoport fixes a couple of issues with the just-merged "arch, mm:
reduce code duplication in mem_init()" series
- The series "MAINTAINERS: add my isub-entries to MM part." from Mike
Rapoport does some maintenance on MAINTAINERS
- The series "remove tlb_remove_page_ptdesc()" from Qi Zheng does some
cleanup work to the page mapping code
- The series "mseal system mappings" from Jeff Xu permits sealing of
"system mappings", such as vdso, vvar, vvar_vclock, vectors (arm
compat-mode), sigpage (arm compat-mode)
- Plus the usual shower of singleton patches
* tag 'mm-stable-2025-04-02-22-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (31 commits)
mseal sysmap: add arch-support txt
mseal sysmap: enable s390
selftest: test system mappings are sealed
mseal sysmap: update mseal.rst
mseal sysmap: uprobe mapping
mseal sysmap: enable arm64
mseal sysmap: enable x86-64
mseal sysmap: generic vdso vvar mapping
selftests: x86: test_mremap_vdso: skip if vdso is msealed
mseal sysmap: kernel config and header change
mm: pgtable: remove tlb_remove_page_ptdesc()
x86: pgtable: convert to use tlb_remove_ptdesc()
riscv: pgtable: unconditionally use tlb_remove_ptdesc()
mm: pgtable: convert some architectures to use tlb_remove_ptdesc()
mm: pgtable: change pt parameter of tlb_remove_ptdesc() to struct ptdesc*
mm: pgtable: make generic tlb_remove_table() use struct ptdesc
microblaze/mm: put mm_cmdline_setup() in .init.text section
mm/memory_hotplug: fix call folio_test_large with tail page in do_migrate_range
MAINTAINERS: mm: add entry for secretmem
MAINTAINERS: mm: add entry for numa memblocks and numa emulation
...
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Pull VFIO updates from Alex Williamson:
- Relax IGD support code to match display class device rather than
specifically requiring a VGA device (Tomita Moeko)
- Accelerate DMA mapping of device MMIO by iterating at PMD and PUD
levels to take advantage of huge pfnmap support added in v6.12
(Alex Williamson)
- Extend virtio vfio-pci variant driver to include migration support
for block devices where enabled by the PF (Yishai Hadas)
- Virtualize INTx PIN register for devices where the platform does not
route legacy PCI interrupts for the device and the interrupt is
reported as IRQ_NOTCONNECTED (Alex Williamson)
* tag 'vfio-v6.15-rc1' of https://github.com/awilliam/linux-vfio:
vfio/pci: Handle INTx IRQ_NOTCONNECTED
vfio/virtio: Enable support for virtio-block live migration
vfio/type1: Use mapping page mask for pfnmaps
mm: Provide address mask in struct follow_pfnmap_args
vfio/type1: Use consistent types for page counts
vfio/type1: Use vfio_batch for vaddr_get_pfns()
vfio/type1: Convert all vaddr_get_pfns() callers to use vfio_batch
vfio/type1: Catch zero from pin_user_pages_remote()
vfio/pci: match IGD devices in display controller class
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Patch series "mseal system mappings", v9.
As discussed during mseal() upstream process [1], mseal() protects the
VMAs of a given virtual memory range against modifications, such as the
read/write (RW) and no-execute (NX) bits. For complete descriptions of
memory sealing, please see mseal.rst [2].
The mseal() is useful to mitigate memory corruption issues where a
corrupted pointer is passed to a memory management system. For example,
such an attacker primitive can break control-flow integrity guarantees
since read-only memory that is supposed to be trusted can become writable
or .text pages can get remapped.
The system mappings are readonly only, memory sealing can protect them
from ever changing to writable or unmmap/remapped as different attributes.
System mappings such as vdso, vvar, vvar_vclock, vectors (arm
compat-mode), sigpage (arm compat-mode), are created by the kernel during
program initialization, and could be sealed after creation.
Unlike the aforementioned mappings, the uprobe mapping is not established
during program startup. However, its lifetime is the same as the
process's lifetime [3]. It could be sealed from creation.
The vsyscall on x86-64 uses a special address (0xffffffffff600000), which
is outside the mm managed range. This means mprotect, munmap, and mremap
won't work on the vsyscall. Since sealing doesn't enhance the vsyscall's
security, it is skipped in this patch. If we ever seal the vsyscall, it
is probably only for decorative purpose, i.e. showing the 'sl' flag in
the /proc/pid/smaps. For this patch, it is ignored.
It is important to note that the CHECKPOINT_RESTORE feature (CRIU) may
alter the system mappings during restore operations. UML(User Mode Linux)
and gVisor, rr are also known to change the vdso/vvar mappings.
Consequently, this feature cannot be universally enabled across all
systems. As such, CONFIG_MSEAL_SYSTEM_MAPPINGS is disabled by default.
To support mseal of system mappings, architectures must define
CONFIG_ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS and update their special
mappings calls to pass mseal flag. Additionally, architectures must
confirm they do not unmap/remap system mappings during the process
lifetime. The existence of this flag for an architecture implies that it
does not require the remapping of thest system mappings during process
lifetime, so sealing these mappings is safe from a kernel perspective.
This version covers x86-64 and arm64 archiecture as minimum viable feature.
While no specific CPU hardware features are required for enable this
feature on an archiecture, memory sealing requires a 64-bit kernel. Other
architectures can choose whether or not to adopt this feature. Currently,
I'm not aware of any instances in the kernel code that actively
munmap/mremap a system mapping without a request from userspace. The PPC
does call munmap when _install_special_mapping fails for vdso; however,
it's uncertain if this will ever fail for PPC - this needs to be
investigated by PPC in the future [4]. The UML kernel can add this
support when KUnit tests require it [5].
In this version, we've improved the handling of system mapping sealing
from previous versions, instead of modifying the _install_special_mapping
function itself, which would affect all architectures, we now call
_install_special_mapping with a sealing flag only within the specific
architecture that requires it. This targeted approach offers two key
advantages: 1) It limits the code change's impact to the necessary
architectures, and 2) It aligns with the software architecture by keeping
the core memory management within the mm layer, while delegating the
decision of sealing system mappings to the individual architecture, which
is particularly relevant since 32-bit architectures never require sealing.
Prior to this patch series, we explored sealing special mappings from
userspace using glibc's dynamic linker. This approach revealed several
issues:
- The PT_LOAD header may report an incorrect length for vdso, (smaller
than its actual size). The dynamic linker, which relies on PT_LOAD
information to determine mapping size, would then split and partially
seal the vdso mapping. Since each architecture has its own vdso/vvar
code, fixing this in the kernel would require going through each
archiecture. Our initial goal was to enable sealing readonly mappings,
e.g. .text, across all architectures, sealing vdso from kernel since
creation appears to be simpler than sealing vdso at glibc.
- The [vvar] mapping header only contains address information, not
length information. Similar issues might exist for other special
mappings.
- Mappings like uprobe are not covered by the dynamic linker, and there
is no effective solution for them.
This feature's security enhancements will benefit ChromeOS, Android, and
other high security systems.
Testing:
This feature was tested on ChromeOS and Android for both x86-64 and ARM64.
- Enable sealing and verify vdso/vvar, sigpage, vector are sealed properly,
i.e. "sl" shown in the smaps for those mappings, and mremap is blocked.
- Passing various automation tests (e.g. pre-checkin) on ChromeOS and
Android to ensure the sealing doesn't affect the functionality of
Chromebook and Android phone.
I also tested the feature on Ubuntu on x86-64:
- With config disabled, vdso/vvar is not sealed,
- with config enabled, vdso/vvar is sealed, and booting up Ubuntu is OK,
normal operations such as browsing the web, open/edit doc are OK.
Link: https://lore.kernel.org/all/20240415163527.626541-1-jeffxu@chromium.org/ [1]
Link: Documentation/userspace-api/mseal.rst [2]
Link: https://lore.kernel.org/all/CABi2SkU9BRUnqf70-nksuMCQ+yyiWjo3fM4XkRkL-NrCZxYAyg@mail.gmail.com/ [3]
Link: https://lore.kernel.org/all/CABi2SkV6JJwJeviDLsq9N4ONvQ=EFANsiWkgiEOjyT9TQSt+HA@mail.gmail.com/ [4]
Link: https://lore.kernel.org/all/202502251035.239B85A93@keescook/ [5]
This patch (of 7):
Provide infrastructure to mseal system mappings. Establish two kernel
configs (CONFIG_MSEAL_SYSTEM_MAPPINGS,
ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS) and VM_SEALED_SYSMAP macro for future
patches.
Link: https://lkml.kernel.org/r/20250305021711.3867874-1-jeffxu@google.com
Link: https://lkml.kernel.org/r/20250305021711.3867874-2-jeffxu@google.com
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Benjamin Berg <benjamin@sipsolutions.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Elliot Hughes <enh@google.com>
Cc: Florian Faineli <f.fainelli@gmail.com>
Cc: Greg Ungerer <gerg@kernel.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Linus Waleij <linus.walleij@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <mike.rapoport@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Röttger <sroettger@google.com>
Cc: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Pull MM updates from Andrew Morton:
- The series "Enable strict percpu address space checks" from Uros
Bizjak uses x86 named address space qualifiers to provide
compile-time checking of percpu area accesses.
This has caused a small amount of fallout - two or three issues were
reported. In all cases the calling code was found to be incorrect.
- The series "Some cleanup for memcg" from Chen Ridong implements some
relatively monir cleanups for the memcontrol code.
- The series "mm: fixes for device-exclusive entries (hmm)" from David
Hildenbrand fixes a boatload of issues which David found then using
device-exclusive PTE entries when THP is enabled. More work is
needed, but this makes thins better - our own HMM selftests now
succeed.
- The series "mm: zswap: remove z3fold and zbud" from Yosry Ahmed
remove the z3fold and zbud implementations. They have been deprecated
for half a year and nobody has complained.
- The series "mm: further simplify VMA merge operation" from Lorenzo
Stoakes implements numerous simplifications in this area. No runtime
effects are anticipated.
- The series "mm/madvise: remove redundant mmap_lock operations from
process_madvise()" from SeongJae Park rationalizes the locking in the
madvise() implementation. Performance gains of 20-25% were observed
in one MADV_DONTNEED microbenchmark.
- The series "Tiny cleanup and improvements about SWAP code" from
Baoquan He contains a number of touchups to issues which Baoquan
noticed when working on the swap code.
- The series "mm: kmemleak: Usability improvements" from Catalin
Marinas implements a couple of improvements to the kmemleak
user-visible output.
- The series "mm/damon/paddr: fix large folios access and schemes
handling" from Usama Arif provides a couple of fixes for DAMON's
handling of large folios.
- The series "mm/damon/core: fix wrong and/or useless damos_walk()
behaviors" from SeongJae Park fixes a few issues with the accuracy of
kdamond's walking of DAMON regions.
- The series "expose mapping wrprotect, fix fb_defio use" from Lorenzo
Stoakes changes the interaction between framebuffer deferred-io and
core MM. No functional changes are anticipated - this is preparatory
work for the future removal of page structure fields.
- The series "mm/damon: add support for hugepage_size DAMOS filter"
from Usama Arif adds a DAMOS filter which permits the filtering by
huge page sizes.
- The series "mm: permit guard regions for file-backed/shmem mappings"
from Lorenzo Stoakes extends the guard region feature from its
present "anon mappings only" state. The feature now covers shmem and
file-backed mappings.
- The series "mm: batched unmap lazyfree large folios during
reclamation" from Barry Song cleans up and speeds up the unmapping
for pte-mapped large folios.
- The series "reimplement per-vma lock as a refcount" from Suren
Baghdasaryan puts the vm_lock back into the vma. Our reasons for
pulling it out were largely bogus and that change made the code more
messy. This patchset provides small (0-10%) improvements on one
microbenchmark.
- The series "Docs/mm/damon: misc DAMOS filters documentation fixes and
improves" from SeongJae Park does some maintenance work on the DAMON
docs.
- The series "hugetlb/CMA improvements for large systems" from Frank
van der Linden addresses a pile of issues which have been observed
when using CMA on large machines.
- The series "mm/damon: introduce DAMOS filter type for unmapped pages"
from SeongJae Park enables users of DMAON/DAMOS to filter my the
page's mapped/unmapped status.
- The series "zsmalloc/zram: there be preemption" from Sergey
Senozhatsky teaches zram to run its compression and decompression
operations preemptibly.
- The series "selftests/mm: Some cleanups from trying to run them" from
Brendan Jackman fixes a pile of unrelated issues which Brendan
encountered while runnimg our selftests.
- The series "fs/proc/task_mmu: add guard region bit to pagemap" from
Lorenzo Stoakes permits userspace to use /proc/pid/pagemap to
determine whether a particular page is a guard page.
- The series "mm, swap: remove swap slot cache" from Kairui Song
removes the swap slot cache from the allocation path - it simply
wasn't being effective.
- The series "mm: cleanups for device-exclusive entries (hmm)" from
David Hildenbrand implements a number of unrelated cleanups in this
code.
- The series "mm: Rework generic PTDUMP configs" from Anshuman Khandual
implements a number of preparatoty cleanups to the GENERIC_PTDUMP
Kconfig logic.
- The series "mm/damon: auto-tune aggregation interval" from SeongJae
Park implements a feedback-driven automatic tuning feature for
DAMON's aggregation interval tuning.
- The series "Fix lazy mmu mode" from Ryan Roberts fixes some issues in
powerpc, sparc and x86 lazy MMU implementations. Ryan did this in
preparation for implementing lazy mmu mode for arm64 to optimize
vmalloc.
- The series "mm/page_alloc: Some clarifications for migratetype
fallback" from Brendan Jackman reworks some commentary to make the
code easier to follow.
- The series "page_counter cleanup and size reduction" from Shakeel
Butt cleans up the page_counter code and fixes a size increase which
we accidentally added late last year.
- The series "Add a command line option that enables control of how
many threads should be used to allocate huge pages" from Thomas
Prescher does that. It allows the careful operator to significantly
reduce boot time by tuning the parallalization of huge page
initialization.
- The series "Fix calculations in trace_balance_dirty_pages() for cgwb"
from Tang Yizhou fixes the tracing output from the dirty page
balancing code.
- The series "mm/damon: make allow filters after reject filters useful
and intuitive" from SeongJae Park improves the handling of allow and
reject filters. Behaviour is made more consistent and the documention
is updated accordingly.
- The series "Switch zswap to object read/write APIs" from Yosry Ahmed
updates zswap to the new object read/write APIs and thus permits the
removal of some legacy code from zpool and zsmalloc.
- The series "Some trivial cleanups for shmem" from Baolin Wang does as
it claims.
- The series "fs/dax: Fix ZONE_DEVICE page reference counts" from
Alistair Popple regularizes the weird ZONE_DEVICE page refcount
handling in DAX, permittig the removal of a number of special-case
checks.
- The series "refactor mremap and fix bug" from Lorenzo Stoakes is a
preparatoty refactoring and cleanup of the mremap() code.
- The series "mm: MM owner tracking for large folios (!hugetlb) +
CONFIG_NO_PAGE_MAPCOUNT" from David Hildenbrand reworks the manner in
which we determine whether a large folio is known to be mapped
exclusively into a single MM.
- The series "mm/damon: add sysfs dirs for managing DAMOS filters based
on handling layers" from SeongJae Park adds a couple of new sysfs
directories to ease the management of DAMON/DAMOS filters.
- The series "arch, mm: reduce code duplication in mem_init()" from
Mike Rapoport consolidates many per-arch implementations of
mem_init() into code generic code, where that is practical.
- The series "mm/damon/sysfs: commit parameters online via
damon_call()" from SeongJae Park continues the cleaning up of sysfs
access to DAMON internal data.
- The series "mm: page_ext: Introduce new iteration API" from Luiz
Capitulino reworks the page_ext initialization to fix a boot-time
crash which was observed with an unusual combination of compile and
cmdline options.
- The series "Buddy allocator like (or non-uniform) folio split" from
Zi Yan reworks the code to split a folio into smaller folios. The
main benefit is lessened memory consumption: fewer post-split folios
are generated.
- The series "Minimize xa_node allocation during xarry split" from Zi
Yan reduces the number of xarray xa_nodes which are generated during
an xarray split.
- The series "drivers/base/memory: Two cleanups" from Gavin Shan
performs some maintenance work on the drivers/base/memory code.
- The series "Add tracepoints for lowmem reserves, watermarks and
totalreserve_pages" from Martin Liu adds some more tracepoints to the
page allocator code.
- The series "mm/madvise: cleanup requests validations and
classifications" from SeongJae Park cleans up some warts which
SeongJae observed during his earlier madvise work.
- The series "mm/hwpoison: Fix regressions in memory failure handling"
from Shuai Xue addresses two quite serious regressions which Shuai
has observed in the memory-failure implementation.
- The series "mm: reliable huge page allocator" from Johannes Weiner
makes huge page allocations cheaper and more reliable by reducing
fragmentation.
- The series "Minor memcg cleanups & prep for memdescs" from Matthew
Wilcox is preparatory work for the future implementation of memdescs.
- The series "track memory used by balloon drivers" from Nico Pache
introduces a way to track memory used by our various balloon drivers.
- The series "mm/damon: introduce DAMOS filter type for active pages"
from Nhat Pham permits users to filter for active/inactive pages,
separately for file and anon pages.
- The series "Adding Proactive Memory Reclaim Statistics" from Hao Jia
separates the proactive reclaim statistics from the direct reclaim
statistics.
- The series "mm/vmscan: don't try to reclaim hwpoison folio" from
Jinjiang Tu fixes our handling of hwpoisoned pages within the reclaim
code.
* tag 'mm-stable-2025-03-30-16-52' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (431 commits)
mm/page_alloc: remove unnecessary __maybe_unused in order_to_pindex()
x86/mm: restore early initialization of high_memory for 32-bits
mm/vmscan: don't try to reclaim hwpoison folio
mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper
cgroup: docs: add pswpin and pswpout items in cgroup v2 doc
mm: vmscan: split proactive reclaim statistics from direct reclaim statistics
selftests/mm: speed up split_huge_page_test
selftests/mm: uffd-unit-tests support for hugepages > 2M
docs/mm/damon/design: document active DAMOS filter type
mm/damon: implement a new DAMOS filter type for active pages
fs/dax: don't disassociate zero page entries
MM documentation: add "Unaccepted" meminfo entry
selftests/mm: add commentary about 9pfs bugs
fork: use __vmalloc_node() for stack allocation
docs/mm: Physical Memory: Populate the "Zones" section
xen: balloon: update the NR_BALLOON_PAGES state
hv_balloon: update the NR_BALLOON_PAGES state
balloon_compaction: update the NR_BALLOON_PAGES state
meminfo: add a per node counter for balloon drivers
mm: remove references to folio in __memcg_kmem_uncharge_page()
...
|
|
Pull ring-buffer updates from Steven Rostedt:
- Restructure the persistent memory to have a "scratch" area
Instead of hard coding the KASLR offset in the persistent memory by
the ring buffer, push that work up to the callers of the persistent
memory as they are the ones that need this information. The offsets
and such is not important to the ring buffer logic and it should not
be part of that.
A scratch pad is now created when the caller allocates a ring buffer
from persistent memory by stating how much memory it needs to save.
- Allow where modules are loaded to be saved in the new scratch pad
Save the addresses of modules when they are loaded into the
persistent memory scratch pad.
- A new module_for_each_mod() helper function was created
With the acknowledgement of the module maintainers a new module
helper function was created to iterate over all the currently loaded
modules. This has a callback to be called for each module. This is
needed for when tracing is started in the persistent buffer and the
currently loaded modules need to be saved in the scratch area.
- Expose the last boot information where the kernel and modules were
loaded
The last_boot_info file is updated to print out the addresses of
where the kernel "_text" location was loaded from a previous boot, as
well as where the modules are loaded. If the buffer is recording the
current boot, it only prints "# Current" so that it does not expose
the KASLR offset of the currently running kernel.
- Allow the persistent ring buffer to be released (freed)
To have this in production environments, where the kernel command
line can not be changed easily, the ring buffer needs to be freed
when it is not going to be used. The memory for the buffer will
always be allocated at boot up, but if the system isn't going to
enable tracing, the memory needs to be freed. Allow it to be freed
and added back to the kernel memory pool.
- Allow stack traces to print the function names in the persistent
buffer
Now that the modules are saved in the persistent ring buffer, if the
same modules are loaded, the printing of the function names will
examine the saved modules. If the module is found in the scratch area
and is also loaded, then it will do the offset shift and use kallsyms
to display the function name. If the address is not found, it simply
displays the address from the previous boot in hex.
* tag 'trace-ringbuffer-v6.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Use _text and the kernel offset in last_boot_info
tracing: Show last module text symbols in the stacktrace
ring-buffer: Remove the unused variable bmeta
tracing: Skip update_last_data() if cleared and remove active check for save_mod()
tracing: Initialize scratch_size to zero to prevent UB
tracing: Fix a compilation error without CONFIG_MODULES
tracing: Freeable reserved ring buffer
mm/memblock: Add reserved memory release function
tracing: Update modules to persistent instances when loaded
tracing: Show module names and addresses of last boot
tracing: Have persistent trace instances save module addresses
module: Add module_for_each_mod() function
tracing: Have persistent trace instances save KASLR offset
ring-buffer: Add ring_buffer_meta_scratch()
ring-buffer: Add buffer meta data for persistent ring buffer
ring-buffer: Use kaslr address instead of text delta
ring-buffer: Fix bytes_dropped calculation issue
|
|
Pull bpf updates from Alexei Starovoitov:
"For this merge window we're splitting BPF pull request into three for
higher visibility: main changes, res_spin_lock, try_alloc_pages.
These are the main BPF changes:
- Add DFA-based live registers analysis to improve verification of
programs with loops (Eduard Zingerman)
- Introduce load_acquire and store_release BPF instructions and add
x86, arm64 JIT support (Peilin Ye)
- Fix loop detection logic in the verifier (Eduard Zingerman)
- Drop unnecesary lock in bpf_map_inc_not_zero() (Eric Dumazet)
- Add kfunc for populating cpumask bits (Emil Tsalapatis)
- Convert various shell based tests to selftests/bpf/test_progs
format (Bastien Curutchet)
- Allow passing referenced kptrs into struct_ops callbacks (Amery
Hung)
- Add a flag to LSM bpf hook to facilitate bpf program signing
(Blaise Boscaccy)
- Track arena arguments in kfuncs (Ihor Solodrai)
- Add copy_remote_vm_str() helper for reading strings from remote VM
and bpf_copy_from_user_task_str() kfunc (Jordan Rome)
- Add support for timed may_goto instruction (Kumar Kartikeya
Dwivedi)
- Allow bpf_get_netns_cookie() int cgroup_skb programs (Mahe Tardy)
- Reduce bpf_cgrp_storage_busy false positives when accessing cgroup
local storage (Martin KaFai Lau)
- Introduce bpf_dynptr_copy() kfunc (Mykyta Yatsenko)
- Allow retrieving BTF data with BTF token (Mykyta Yatsenko)
- Add BPF kfuncs to set and get xattrs with 'security.bpf.' prefix
(Song Liu)
- Reject attaching programs to noreturn functions (Yafang Shao)
- Introduce pre-order traversal of cgroup bpf programs (Yonghong
Song)"
* tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (186 commits)
selftests/bpf: Add selftests for load-acquire/store-release when register number is invalid
bpf: Fix out-of-bounds read in check_atomic_load/store()
libbpf: Add namespace for errstr making it libbpf_errstr
bpf: Add struct_ops context information to struct bpf_prog_aux
selftests/bpf: Sanitize pointer prior fclose()
selftests/bpf: Migrate test_xdp_vlan.sh into test_progs
selftests/bpf: test_xdp_vlan: Rename BPF sections
bpf: clarify a misleading verifier error message
selftests/bpf: Add selftest for attaching fexit to __noreturn functions
bpf: Reject attaching fexit/fmod_ret to __noreturn functions
bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage
bpf: Make perf_event_read_output accessible in all program types.
bpftool: Using the right format specifiers
bpftool: Add -Wformat-signedness flag to detect format errors
selftests/bpf: Test freplace from user namespace
libbpf: Pass BPF token from find_prog_btf_id to BPF_BTF_GET_FD_BY_ID
bpf: Return prog btf_id without capable check
bpf: BPF token support for BPF_BTF_GET_FD_BY_ID
bpf, x86: Fix objtool warning for timed may_goto
bpf: Check map->record at the beginning of check_and_free_fields()
...
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Add reserve_mem_release_by_name() to release a reserved memory region
with a given name. This allows us to release reserved memory which is
defined by kernel cmdline, after boot.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/173989133862.230693.14094993331347437600.stgit@devnote2
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
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Pull sysctl updates from Joel Granados:
- Move vm_table members out of kernel/sysctl.c
All vm_table array members have moved to their respective subsystems
leading to the removal of vm_table from kernel/sysctl.c. This
increases modularity by placing the ctl_tables closer to where they
are actually used and at the same time reducing the chances of merge
conflicts in kernel/sysctl.c.
- ctl_table range fixes
Replace the proc_handler function that checks variable ranges in
coredump_sysctls and vdso_table with the one that actually uses the
extra{1,2} pointers as min/max values. This tightens the range of the
values that users can pass into the kernel effectively preventing
{under,over}flows.
- Misc fixes
Correct grammar errors and typos in test messages. Update sysctl
files in MAINTAINERS. Constified and removed array size in
declaration for alignment_tbl
* tag 'sysctl-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: (22 commits)
selftests/sysctl: fix wording of help messages
selftests: fix spelling/grammar errors in sysctl/sysctl.sh
MAINTAINERS: Update sysctl file list in MAINTAINERS
sysctl: Fix underflow value setting risk in vm_table
coredump: Fixes core_pipe_limit sysctl proc_handler
sysctl: remove unneeded include
sysctl: remove the vm_table
sh: vdso: move the sysctl to arch/sh/kernel/vsyscall/vsyscall.c
x86: vdso: move the sysctl to arch/x86/entry/vdso/vdso32-setup.c
fs: dcache: move the sysctl to fs/dcache.c
sunrpc: simplify rpcauth_cache_shrink_count()
fs: drop_caches: move sysctl to fs/drop_caches.c
fs: fs-writeback: move sysctl to fs/fs-writeback.c
mm: nommu: move sysctl to mm/nommu.c
security: min_addr: move sysctl to security/min_addr.c
mm: mmap: move sysctl to mm/mmap.c
mm: util: move sysctls to mm/util.c
mm: vmscan: move vmscan sysctls to mm/vmscan.c
mm: swap: move sysctl to mm/swap.c
mm: filemap: move sysctl to mm/filemap.c
...
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Pull misc vfs updates from Christian Brauner:
"Features:
- Add CONFIG_DEBUG_VFS infrastucture:
- Catch invalid modes in open
- Use the new debug macros in inode_set_cached_link()
- Use debug-only asserts around fd allocation and install
- Place f_ref to 3rd cache line in struct file to resolve false
sharing
Cleanups:
- Start using anon_inode_getfile_fmode() helper in various places
- Don't take f_lock during SEEK_CUR if exclusion is guaranteed by
f_pos_lock
- Add unlikely() to kcmp()
- Remove legacy ->remount_fs method from ecryptfs after port to the
new mount api
- Remove invalidate_inodes() in favour of evict_inodes()
- Simplify ep_busy_loopER by removing unused argument
- Avoid mmap sem relocks when coredumping with many missing pages
- Inline getname()
- Inline new_inode_pseudo() and de-staticize alloc_inode()
- Dodge an atomic in putname if ref == 1
- Consistently deref the files table with rcu_dereference_raw()
- Dedup handling of struct filename init and refcounts bumps
- Use wq_has_sleeper() in end_dir_add()
- Drop the lock trip around I_NEW wake up in evict()
- Load the ->i_sb pointer once in inode_sb_list_{add,del}
- Predict not reaching the limit in alloc_empty_file()
- Tidy up do_sys_openat2() with likely/unlikely
- Call inode_sb_list_add() outside of inode hash lock
- Sort out fd allocation vs dup2 race commentary
- Turn page_offset() into a wrapper around folio_pos()
- Remove locking in exportfs around ->get_parent() call
- try_lookup_one_len() does not need any locks in autofs
- Fix return type of several functions from long to int in open
- Fix return type of several functions from long to int in ioctls
Fixes:
- Fix watch queue accounting mismatch"
* tag 'vfs-6.15-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
fs: sort out fd allocation vs dup2 race commentary, take 2
fs: call inode_sb_list_add() outside of inode hash lock
fs: tidy up do_sys_openat2() with likely/unlikely
fs: predict not reaching the limit in alloc_empty_file()
fs: load the ->i_sb pointer once in inode_sb_list_{add,del}
fs: drop the lock trip around I_NEW wake up in evict()
fs: use wq_has_sleeper() in end_dir_add()
VFS/autofs: try_lookup_one_len() does not need any locks
fs: dedup handling of struct filename init and refcounts bumps
fs: consistently deref the files table with rcu_dereference_raw()
exportfs: remove locking around ->get_parent() call.
fs: use debug-only asserts around fd allocation and install
fs: dodge an atomic in putname if ref == 1
vfs: Remove invalidate_inodes()
ecryptfs: remove NULL remount_fs from super_operations
watch_queue: fix pipe accounting mismatch
fs: place f_ref to 3rd cache line in struct file to resolve false sharing
epoll: simplify ep_busy_loop by removing always 0 argument
fs: Turn page_offset() into a wrapper around folio_pos()
kcmp: improve performance adding an unlikely hint to task comparisons
...
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Pull misc hotfixes from Andrew Morton:
"15 hotfixes. 7 are cc:stable and the remainder address post-6.13
issues or aren't considered necessary for -stable kernels.
13 are for MM and the other two are for squashfs and procfs.
All are singletons. Please see the individual changelogs for details"
* tag 'mm-hotfixes-stable-2025-03-17-20-09' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/page_alloc: fix memory accept before watermarks gets initialized
mm: decline to manipulate the refcount on a slab page
memcg: drain obj stock on cpu hotplug teardown
mm/huge_memory: drop beyond-EOF folios with the right number of refs
selftests/mm: run_vmtests.sh: fix half_ufd_size_MB calculation
mm: fix error handling in __filemap_get_folio() with FGP_NOWAIT
mm: memcontrol: fix swap counter leak from offline cgroup
mm/vma: do not register private-anon mappings with khugepaged during mmap
squashfs: fix invalid pointer dereference in squashfs_cache_delete
mm/migrate: fix shmem xarray update during migration
mm/hugetlb: fix surplus pages in dissolve_free_huge_page()
mm/damon/core: initialize damos->walk_completed in damon_new_scheme()
mm/damon: respect core layer filters' allowance decision on ops layer
filemap: move prefaulting out of hot write path
proc: fix UAF in proc_get_inode()
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Currently, implementation of mem_init() in every architecture consists of
one or more of the following:
* initializations that must run before page allocator is active, for
instance swiotlb_init()
* a call to memblock_free_all() to release all the memory to the buddy
allocator
* initializations that must run after page allocator is ready and there is
no arch-specific hook other than mem_init() for that, like for example
register_page_bootmem_info() in x86 and sparc64 or simple setting of
mem_init_done = 1 in several architectures
* a bunch of semi-related stuff that apparently had no better place to
live, for example a ton of BUILD_BUG_ON()s in parisc.
Introduce arch_mm_preinit() that will be the first thing called from
mm_core_init(). On architectures that have initializations that must happen
before the page allocator is ready, move those into arch_mm_preinit() along
with the code that does not depend on ordering with page allocator setup.
On several architectures this results in reduction of mem_init() to a
single call to memblock_free_all() that allows its consolidation next.
Link: https://lkml.kernel.org/r/20250313135003.836600-13-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com> [x86]
Tested-by: Mark Brown <broonie@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren (csky) <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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All architectures that support HIGHMEM have their code that frees high
memory pages to the buddy allocator while __free_memory_core() is limited
to freeing only low memory.
There is no actual reason for that. The memory map is completely ready by
the time memblock_free_all() is called and high pages can be released to
the buddy allocator along with low memory.
Remove low memory limit from __free_memory_core() and drop per-architecture
code that frees high memory pages.
Link: https://lkml.kernel.org/r/20250313135003.836600-12-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com> [x86]
Tested-by: Mark Brown <broonie@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren (csky) <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
max_mapnr is essentially the size of the memory map for systems that use
FLATMEM. There is no reason to calculate it in each and every architecture
when it's anyway calculated in alloc_node_mem_map().
Drop setting of max_mapnr from architecture code and set it once in
alloc_node_mem_map().
While on it, move definition of mem_map and max_mapnr to mm/mm_init.c so
there won't be two copies for MMU and !MMU variants.
Link: https://lkml.kernel.org/r/20250313135003.836600-10-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com> [x86]
Tested-by: Mark Brown <broonie@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren (csky) <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Let's reuse our new MM ownership tracking infrastructure for large folios
to make folio_likely_mapped_shared() never return false negatives -- never
indicating "not mapped shared" although the folio *is* mapped shared.
With that, we can rename it to folio_maybe_mapped_shared() and get rid of
the dependency on the mapcount of the first folio page.
The semantics are now arguably clearer: no mixture of "false negatives"
and "false positives", only the remaining possibility for "false
positives".
Thoroughly document the new semantics. We might now detect that a large
folio is "maybe mapped shared" although it *no longer* is -- but once was.
Now, if more than two MMs mapped a folio at the same time, and the MM
mapping the folio exclusively at the end is not one tracked in the two
folio MM slots, we will detect the folio as "maybe mapped shared".
For anonymous folios, usually (except weird corner cases) all PTEs that
target a "maybe mapped shared" folio are R/O. As soon as a child process
would write to them (iow, actively use them), we would CoW and effectively
replace these PTEs. Most cases (below) are not expected to really matter
with large anonymous folios for this reason.
Most importantly, there will be no change at all for:
* small folios
* hugetlb folios
* PMD-mapped PMD-sized THPs (single mapping)
This change has the potential to affect existing callers of
folio_likely_mapped_shared() -> folio_maybe_mapped_shared():
(1) fs/proc/task_mmu.c: no change (hugetlb)
(2) khugepaged counts PTEs that target shared folios towards
max_ptes_shared (default: HPAGE_PMD_NR / 2), meaning we could skip a
collapse where we would have previously collapsed. This only applies
to anonymous folios and is not expected to matter in practice.
Worth noting that this change sorts out case (A) documented in
commit 1bafe96e89f0 ("mm/khugepaged: replace page_mapcount() check by
folio_likely_mapped_shared()") by removing the possibility for "false
negatives".
(3) MADV_COLD / MADV_PAGEOUT / MADV_FREE will not try splitting
PTE-mapped THPs that are considered shared but not fully covered by
the requested range, consequently not processing them.
PMD-mapped PMD-sized THP are not affected, or when all PTEs are
covered. These functions are usually only called on anon/file folios
that are exclusively mapped most of the time (no other file mappings
or no fork()), so the "false negatives" are not expected to matter in
practice.
(4) mbind() / migrate_pages() / move_pages() will refuse to migrate
shared folios unless MPOL_MF_MOVE_ALL is effective (requires
CAP_SYS_NICE). We will now reject some folios that could be migrated.
Similar to (3), especially with MPOL_MF_MOVE_ALL, so this is not
expected to matter in practice.
Note that cpuset_migrate_mm_workfn() calls do_migrate_pages() with
MPOL_MF_MOVE_ALL.
(5) NUMA hinting
mm/migrate.c:migrate_misplaced_folio_prepare() will skip file
folios that are probably shared libraries (-> "mapped shared" and
executable). This check would have detected it as a shared library at
some point (at least 3 MMs mapping it), so detecting it afterwards
does not sound wrong (still a shared library). Not expected to
matter.
mm/memory.c:numa_migrate_check() will indicate TNF_SHARED in
MAP_SHARED file mappings when encountering a shared folio. Similar
reasoning, not expected to matter.
mm/mprotect.c:change_pte_range() will skip folios detected as
shared in CoW mappings. Similarly, this is not expected to matter in
practice, but if it would ever be a problem we could relax that check
a bit (e.g., basing it on the average page-mapcount in a folio),
because it was only an optimization when many (e.g., 288) processes
were mapping the same folios -- see commit 859d4adc3415 ("mm: numa: do
not trap faults on shared data section pages.")
(6) mm/rmap.c:folio_referenced_one() will skip exclusive swapbacked
folios in dying processes. Applies to anonymous folios only. Without
"false negatives", we'll now skip all actually shared ones. Skipping
ones that are actually exclusive won't really matter, it's a pure
optimization, and is not expected to matter in practice.
In theory, one can detect the problematic scenario: folio_mapcount() > 0
and no folio MM slot is occupied ("state unknown"). One could reset the
MM slots while doing an rmap walk, which migration / folio split already
do when setting everything up. Further, when batching PTEs we might
naturally learn about a owner (e.g., folio_mapcount() == nr_ptes) and
could update the owner. However, we'll defer that until the scenarios
where it would really matter are clear.
Link: https://lkml.kernel.org/r/20250303163014.1128035-15-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Let's free up some space on 32bit in page[1] by moving the _pincount to
page[2].
Ordinary folios only use the entire mapcount with PMD mappings, so order-1
folios don't apply. Similarly, hugetlb folios are always larger than
order-1, turning the entire mapcount essentially unused for all order-1
folios. Moving it to order-1 folios will not change anything.
On 32bit, simply check in folio_entire_mapcount() whether we have an
order-1 folio, and return 0 in that case.
Note that THPs on 32bit are not particularly common (and we don't care too
much about performance), but we want to keep it working reliably, because
likely we want to use large folios there as well in the future,
independent of PMD leaf support.
Once we dynamically allocate "struct folio", the 32bit specifics will go
away again; even small folios could then have a pincount.
Link: https://lkml.kernel.org/r/20250303163014.1128035-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Let's free up some space on 32bit in page[1] by moving the _pincount to
page[2].
For order-1 folios (never anon folios!) on 32bit, we will now also use the
GUP_PIN_COUNTING_BIAS approach. A fully-mapped order-1 folio requires 2
references. With GUP_PIN_COUNTING_BIAS being 1024, we'd detect such
folios as "maybe pinned" with 512 full mappings, instead of 1024 for
order-0. As anon folios are out of the picture (which are the most
relevant users of checking for pinnings on *mapped* pages) and we are
talking about 32bit, this is not expected to cause any trouble.
In __dump_page(), copy one additional folio page if we detect a folio with
an order > 1, so we can dump the pincount on order > 1 folios reliably.
Note that THPs on 32bit are not particularly common (and we don't care too
much about performance), but we want to keep it working reliably, because
likely we want to use large folios there as well in the future,
independent of PMD leaf support.
Once we dynamically allocate "struct folio", fortunately the 32bit
specifics will likely go away again; even small folios could then have a
pincount and folio_has_pincount() would essentially always return "true".
Link: https://lkml.kernel.org/r/20250303163014.1128035-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Let's free up some more of the "unconditionally available on 64BIT" space
in order-1 folios by letting _folio_nr_pages overlay memcg_data in the
first tail page (second folio page). Consequently, we have the
optimization now whenever we have CONFIG_MEMCG, independent of 64BIT.
We have to make sure that page->memcg on tail pages does not return
"surprises". page_memcg_check() already properly refuses PageTail().
Let's do that earlier in print_page_owner_memcg() to avoid printing wrong
"Slab cache page" information. No other code should touch that field on
tail pages of compound pages.
Reset the "_nr_pages" to 0 when splitting folios, or when freeing them
back to the buddy (to avoid false page->memcg_data "bad page" reports).
Note that in __split_huge_page(), folio_nr_pages() would stop working
already as soon as we start messing with the subpages.
Most kernel configs should have at least CONFIG_MEMCG enabled, even if
disabled at runtime. 64byte "struct memmap" is what we usually have on
64BIT.
While at it, rename "_folio_nr_pages" to "_nr_pages".
Hopefully memdescs / dynamically allocating "strut folio" in the future
will further clean this up, e.g., making _nr_pages available in all
configs and maybe even in small folios. Doing that should be fairly easy
on top of this change.
[david@redhat.com: make "make htmldoc" happy]
Link: https://lkml.kernel.org/r/a97f8a91-ec41-4796-81e3-7c9e0e491ba4@redhat.com
Link: https://lkml.kernel.org/r/20250303163014.1128035-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Let's factor it out into a simple helper function. This helper will also
come in handy when working with code where we know that our folio is
large.
While at it, let's consistently return a "long" value from all these
similar functions. Note that we cannot use "unsigned int" (even though
_folio_nr_pages is of that type), because it would break some callers that
do stuff like "-folio_nr_pages()". Both "int" or "unsigned long" would
work as well.
Maybe in the future we'll have the nr_pages readily available for all
large folios, maybe even for small folios, or maybe for none.
Link: https://lkml.kernel.org/r/20250303163014.1128035-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: MM owner tracking for large folios (!hugetlb) +
CONFIG_NO_PAGE_MAPCOUNT", v3.
Let's add an "easy" way to decide -- without false positives, without
page-mapcounts and without page table/rmap scanning -- whether a large
folio is "certainly mapped exclusively" into a single MM, or whether it
"maybe mapped shared" into multiple MMs.
Use that information to implement Copy-on-Write reuse, to convert
folio_likely_mapped_shared() to folio_maybe_mapped_share(), and to
introduce a kernel config option that lets us not use+maintain per-page
mapcounts in large folios anymore.
The bigger picture was presented at LSF/MM [1].
This series is effectively a follow-up on my early work [2], which
implemented a more precise, but also more complicated, way to identify
whether a large folio is "mapped shared" into multiple MMs or "mapped
exclusively" into a single MM.
1 Patch Organization
====================
Patch #1 -> #6: make more room in order-1 folios, so we have two
"unsigned long" available for our purposes
Patch #7 -> #11: preparations
Patch #12: MM owner tracking for large folios
Patch #13: COW reuse for PTE-mapped anon THP
Patch #14: folio_maybe_mapped_shared()
Patch #15 -> #20: introduce and implement CONFIG_NO_PAGE_MAPCOUNT
2 MM owner tracking
===================
We assign each MM a unique ID ("MM ID"), to be able to squeeze more
information in our folios. On 32bit we use 15-bit IDs, on 64bit we use
31-bit IDs.
For each large folios, we now store two MM-ID+mapcount ("slot")
combinations:
* mm0_id + mm0_mapcount
* mm1_id + mm1_mapcount
On 32bit, we use a 16-bit per-MM mapcount, on 64bit an ordinary 32bit
mapcount. This way, we require 2x "unsigned long" on 32bit and 64bit for
both slots.
Paired with the large mapcount, we can reliably identify whether one of
these MMs is the current owner (-> owns all mappings) or even holds all
folio references (-> owns all mappings, and all references are from
mappings).
As long as only two MMs map folio pages at a time, we can reliably and
precisely identify whether a large folio is "mapped shared" or "mapped
exclusively".
Any additional MM that starts mapping the folio while there are no free
slots becomes an "untracked MM". If one such "untracked MM" is the last
one mapping a folio exclusively, we will not detect the folio as "mapped
exclusively" but instead as "maybe mapped shared". (exception: only a
single mapping remains)
So that's where the approach gets imprecise.
For now, we use a bit-spinlock to sync the large mapcount + slots, and
make sure we do keep the machinery fast, to not degrade (un)map
performance drastically: for example, we make sure to only use a single
atomic (when grabbing the bit-spinlock), like we would already perform
when updating the large mapcount.
3 CONFIG_NO_PAGE_MAPCOUNT
=========================
patch #15 -> #20 spell out and document what exactly is affected when not
maintaining the per-page mapcounts in large folios anymore.
Most importantly, as we cannot maintain folio->_nr_pages_mapped anymore
when (un)mapping pages, we'll account a complete folio as mapped if a
single page is mapped. In addition, we'll not detect partially mapped
anonymous folios as such in all cases yet.
Likely less relevant changes include that we might now under-estimate the
USS (Unique Set Size) of a process, but never over-estimate it.
The goal is to make CONFIG_NO_PAGE_MAPCOUNT the default at some point, to
then slowly make it the only option, as we learn about real-life impacts
and possible ways to mitigate them.
4 Performance
=============
Detailed performance numbers were included in v1 [3], and not that much
changed between v1 and v2.
I did plenty of measurements on different systems in the meantime, that
all revealed slightly different results.
The pte-mapped-folio micro-benchmarks [4] are fairly sensitive to code
layout changes on some systems. Especially the fork() benchmark started
being more-shaky-than-before on recent kernels for some reason.
In summary, with my micro-benchmarks:
* Small folios are not impacted.
* CoW performance seems to be mostly unchanged across all folios sizes.
* CoW reuse performance of large folios now matches CoW reuse
performance of small folios, because we now actually implement the CoW
reuse optimization. On an Intel Xeon Silver 4210R I measured a ~65%
reduction in runtime, on an arm64 system I measured ~54% reduction.
* munmap() performance improves with CONFIG_NO_PAGE_MAPCOUNT. I saw
double-digit % reduction (up to ~30% on an Intel Xeon Silver 4210R and
up to ~70% on an AmpereOne A192-32X) with larger folios. The larger the
folios, the larger the performance improvement.
* munmao() performance very slightly (couple percent) degrades without
CONFIG_NO_PAGE_MAPCOUNT for smaller folios. For larger folios, there
seems to be no change at all.
* fork() performance improves with CONFIG_NO_PAGE_MAPCOUNT. I saw
double-digit % reduction (up to ~20% on an Intel Xeon Silver 4210R and
up to ~10% on an AmpereOne A192-32X) with larger folios. The larger the
folios, the larger the performance improvement.
* While fork() performance without CONFIG_NO_PAGE_MAPCOUNT seems to be
almost unchanged on some systems, I saw some degradation for smaller
folios on the AmpereOne A192-32X. I did not investigate the details
yet, but I suspect code layout changes or suboptimal code placement /
inlining.
I'm not to worried about the fork() micro-benchmarks for smaller folios
given how shaky the results are lately and by how much we improved fork()
performance recently.
I also ran case-anon-cow-rand and case-anon-cow-seq part of
vm-scalability, to assess the scalability and the impact of the
bit-spinlock. My measurements on a two 2-socket 10-core Intel Xeon Silver
4210R CPU revealed no significant changes.
Similarly, running these benchmarks with 2 MiB THPs enabled on the
AmpereOne A192-32X with 192 cores, I got < 1% difference with < 1% stdev,
which is nice.
So far, I did not get my hands on a similarly large system with multiple
sockets.
I found no other fitting scalability benchmarks that seem to really hammer
on concurrent mapping/unmapping of large folio pages like
case-anon-cow-seq does.
5 Concerns
==========
5.1 Bit spinlock
----------------
I'm not quite happy about the bit-spinlock, but so far it does not seem to
affect scalability in my measurements.
If it ever becomes a problem we could either investigate improving the
locking, or simply stopping the MM tracking once there are "too many
mappings" and simply assume that the folio is "mapped shared" until it was
freed.
This would be similar (but slightly different) to the "0,1,2,stopped"
counting idea Willy had at some point. Adding that logic to "stop
tracking" adds more code to the hot path, so I avoided that for now.
5.2 folio_maybe_mapped_shared()
-------------------------------
I documented the change from folio_likely_mapped_shared() to
folio_maybe_mapped_shared() quite extensively. If we run into surprises,
I have some ideas on how to resolve them. For now, I think we should be
fine.
5.3 Added code to map/unmap hot path
------------------------------------
So far, it looks like the added code on the rmap hot path does not really
seem to matter much in the bigger picture. I'd like to further reduce it
(and possibly improve fork() performance further), but I don't easily see
how right now. Well, and I am out of puff 🙂
Having that said, alternatives I considered (e.g., per-MM per-folio
mapcount) would add a lot more overhead to these hot paths.
6 Future Work
=============
6.1 Large mapcount
------------------
It would be very handy if the large mapcount would count how often folio
pages are actually mapped into page tables: a PMD on x86-64 would count
512 times. Calculating the average per-page mapcount will be easy, and
remapping (PMD->PTE) folios would get even faster.
That would also remove the need for the entire mapcount (except for
PMD-sized folios for memory statistics reasons ...), and allow for mapping
folios larger than PMDs (e.g., 4 MiB) easily.
We likely would also have to take the same number of folio references to
make our folio_mapcount() == folio_ref_count() work, and we'd want to be
able to avoid mapcount+refcount overflows: this could already become an
issue with pte-mapped PUD-sized folios (fsdax).
One approach we discussed in the THP cabal meeting is (1) extending the
mapcount for large folios to 64bit (at least on 64bit systems) and (2)
keeping the refcount at 32bit, but (3) having exactly one reference if the
the mapcount != 0.
It should be doable, but there are some corner cases to consider on the
unmap path; it is something that I will be looking into next.
6.2 hugetlb
-----------
I'd love to make use of the same tracking also for hugetlb.
The real problem is PMD table sharing: getting a page mapped by MM X and
unmapped by MM Y will not work. With mshare, that problem should not
exist (all mapping/unmapping will be routed through the mshare MM).
[1] https://lwn.net/Articles/974223/
[2] https://lore.kernel.org/linux-mm/a9922f58-8129-4f15-b160-e0ace581bcbe@redhat.com/T/
[3] https://lkml.kernel.org/r/20240829165627.2256514-1-david@redhat.com
[4] https://gitlab.com/davidhildenbrand/scratchspace/-/raw/main/pte-mapped-folio-benchmarks.c
This patch (of 20):
Let's factor it out into a simple helper function. This helper will also
come in handy when working with code where we know that our folio is
large.
Maybe in the future we'll have the order readily available for small and
large folios; in that case, folio_large_order() would simply translate to
folio_order().
Link: https://lkml.kernel.org/r/20250303163014.1128035-1-david@redhat.com
Link: https://lkml.kernel.org/r/20250303163014.1128035-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirks^H^Hski <luto@kernel.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: tejun heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Currently fs dax pages are considered free when the refcount drops to one
and their refcounts are not increased when mapped via PTEs or decreased
when unmapped. This requires special logic in mm paths to detect that
these pages should not be properly refcounted, and to detect when the
refcount drops to one instead of zero.
On the other hand get_user_pages(), etc. will properly refcount fs dax
pages by taking a reference and dropping it when the page is unpinned.
Tracking this special behaviour requires extra PTE bits (eg. pte_devmap)
and introduces rules that are potentially confusing and specific to FS DAX
pages. To fix this, and to possibly allow removal of the special PTE bits
in future, convert the fs dax page refcounts to be zero based and instead
take a reference on the page each time it is mapped as is currently the
case for normal pages.
This may also allow a future clean-up to remove the pgmap refcounting that
is currently done in mm/gup.c.
Link: https://lkml.kernel.org/r/c7d886ad7468a20452ef6e0ddab6cfe220874e7c.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Longterm pinning of FS DAX pages should already be disallowed by various
pXX_devmap checks. However a future change will cause these checks to be
invalid for FS DAX pages so make folio_is_longterm_pinnable() return false
for FS DAX pages.
Link: https://lkml.kernel.org/r/250a31876704b79f7c65b159f3c835e547f052df.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Currently to map a DAX page the DAX driver calls vmf_insert_pfn. This
creates a special devmap PTE entry for the pfn but does not take a
reference on the underlying struct page for the mapping. This is because
DAX page refcounts are treated specially, as indicated by the presence of
a devmap entry.
To allow DAX page refcounts to be managed the same as normal page
refcounts introduce vmf_insert_page_mkwrite(). This will take a reference
on the underlying page much the same as vmf_insert_page, except it also
permits upgrading an existing mapping to be writable if
requested/possible.
Link: https://lkml.kernel.org/r/4ce3aa984c060f370105e0bfef1035869578be47.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Dan Wiliams <dan.j.williams@intel.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Add a few functions to enable early HVO:
vmemmap_populate_hvo
vmemmap_undo_hvo
vmemmap_wrprotect_hvo
The populate and undo functions are expected to be used in early init,
from the sparse_init_nid_early() function. The wrprotect function is to
be used, potentially, later.
To implement these functions, mostly re-use the existing compound pages
vmemmap logic used by DAX. vmemmap_populate_address has its argument
changed a bit in this commit: the page structure passed in to be reused in
the mapping is replaced by a PFN and a flag. The flag indicates whether
an extra ref should be taken on the vmemmap page containing the head page
structure. Taking the ref is appropriate to for DAX / ZONE_DEVICE, but
not for HugeTLB HVO.
The HugeTLB vmemmap optimization maps tail page structure pages read-only.
The vmemmap_wrprotect_hvo function that does this is implemented
separately, because it cannot be guaranteed that reserved page structures
will not be write accessed during memory initialization. Even with
CONFIG_DEFERRED_STRUCT_PAGE_INIT, they might still be written to (if they
are at the bottom of a zone). So, vmemmap_populate_hvo leaves the tail
page structure pages RW initially, and then later during initialization,
after memmap init is fully done, vmemmap_wrprotect_hvo must be called to
finish the job.
Subsequent commits will use these functions for early HugeTLB HVO.
Link: https://lkml.kernel.org/r/20250228182928.2645936-15-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Add functions that are called just before the per-section memmap is
initialized and just before the memmap page structures are initialized.
They are called sparse_vmemmap_init_nid_early and
sparse_vmemmap_init_nid_late, respectively.
This allows for mm subsystems to add calls to initialize memmap and page
structures in a specific way, if using SPARSEMEM_VMEMMAP. Specifically,
hugetlb can pre-HVO bootmem allocated pages that way, so that no time and
resources are wasted on allocating vmemmap pages, only to free them later
(and possibly unnecessarily running the system out of memory in the
process).
Refactor some code and export a few convenience functions for external
use.
In sparse_init_nid, skip any sections that are already initialized, e.g.
they have been initialized by sparse_vmemmap_init_nid_early already.
The hugetlb code to use these functions will be added in a later commit.
Export section_map_size, as any alternate memmap init code will want to
use it.
The internal config option to enable this is SPARSEMEM_VMEMMAP_PREINIT,
which is selected if an architecture-specific option,
ARCH_WANT_HUGETLB_VMEMMAP_PREINIT, is set. In the future, if other
subsystems want to do preinit too, they can do it in a similar fashion.
The internal config option is there because a section flag is used, and
the number of flags available is architecture-dependent (see mmzone.h).
Architecures can decide if there is room for the flag when enabling
options that select SPARSEMEM_VMEMMAP_PREINIT.
Fortunately, as of right now, all sparse vmemmap using architectures do
have room.
Link: https://lkml.kernel.org/r/20250228182928.2645936-11-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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If other mm code wants to use this function for early memmap inialization
(on the platforms that have it), it should be made available properly, not
just unconditionally in mm.h
Make this function available for such cases.
Link: https://lkml.kernel.org/r/20250228182928.2645936-10-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
Linus Torvalds
Matthew Wilcox (Oracle)
Baolin Wang
David Hildenbrand
Florent Revest
Lorenzo Stoakes
Shivank Garg
Lance Yang
Kevin Brodsky
Ignacio Encinas
Jakub Kicinski
Toke Høiland-Jørgensen
Jeff Xu
Masami Hiramatsu (Google)
Mike Rapoport (Microsoft)
Alistair Popple
Frank van der Linden